The present invention relates to electrostatic copying machines in general, and more particularly to improvements in copying machines of the type wherein a moving exposing device projects an electrostatic image of an original onto a flat photosensitive surface while the surface is at a standstill. Still more particularly, the invention relates to improvements in electrostatic copying machines of the type wherein the exposing device projects a series of line images of an original onto a photosensitive surface which is provided on a mobile backing member.
It is known to employ in an electrostatic copying machine an exposing device which comprises several strip-shaped optical imaging components each of which includes a plurality of lens elements. Such lens elements are used to expose line images of the original while the carriage for the exposing device moves with respect to the original and also with respect to the photosensitive surface on the backing member. Each line image consists of several image portions which are at least contiguous to but may partially overlap each other. It is also known to mount on the carriage one or more light sources (e.g., fluorescent tubes) which illuminate the original while the carriage moves relative to the support for the original and relative to the photosensitive surface. In such machines, the developing device which converts the electrostatic image into a powder image occupies a relatively large amount of space and the carriage must move along a relatively long path. This contributes to the bulk of the copying machine.